Three times in the past six months, the conservative radio host eschewed his usual targets to warn listeners that the sport is under attack, besieged by liberals and threatened with extinction.

“It’s not going to be long before the wusses, the New Castrati in our society are going to suggest that football be banned, that tackle football be banned,” Mr. Limbaugh said during a broadcast in December.

Hyperbole aside, Mr. Limbaugh may have a point. Long a refuge from national political polarization — Tom Brady’s quarterback rating is just as awesome in the red states; our fantasy squads are equally as hopeless in the blue states — football recently has been engulfed in a high-profile public debate about its safety and viability, an argument that echoes previous cultural clashes over everything from cigarettes to semi-automatic weapons.

“I think what we have with football right now is a very old debate in our society,” said Dave Zirin, who writes about the politics of sports for the Nation and authored “A People’s History of Sports in the United States.” “In some ways it’s an argument between individual choice and state intervention.

“In one camp, you have conservatives who are almost like libertarians in terms of certain freedoms. Then you have the kind of nanny-state approach of saying the state needs to step in and remove people’s toys because they are so inherently harmful. We saw the same lines around Prohibition and issues like motorcycle helmets.”

A bubbling debate

For much of the past half century, football has served as an apolitical uniter, the athletic equivalent of apple pie. In the red-state South, the college game is an unofficial civic religion; in blue states such as New York and California, the National Football League is wildly popular; in large cities and small towns alike, high school football teams serve as community totems; from coast to coast, Super Bowl Sunday has become a de facto national holiday.

Recent medical research, however, suggests that football — violent by design — is much more hazardous to the brain health of its participants than once believed.

At every level of the sport, studies indicate, players risk cognitive damage through concussions and repetitive sub-concussive hits to the head, neither of which can be prevented by wearing protective helmets. Short term effects can include headaches, dizziness, confusion and irrational behavior; long term effects can include memory loss, depression, dementia and chronic traumatic encephalopathy (CTE), an Alzheimer’s-like disease previously associated with former prizefighters.

Last year, former Chicago Bears safety Dave Duerson made national headlines after committing suicide by shooting himself in the chest, the better to donate his brain to science; researchers subsequently found signs of CTE. The same disease has been found in the brains of other deceased football players — including some who suffered mental illness and/or took their own lives — and when popular former NFL linebacker Junior Seau killed himself earlier this month, a bubbling national debate erupted.

Retired NFL quarterback Kurt Warner and other former and current professional players wondered if football was safe for their children. ESPN columnist Ashley Fox was one of many writers to declare that her son would never play the sport. Some argued that football needs radical alteration to reduce physical contact. On ABC’s “This Week,” conservative pundit George Will said the game was in trouble, because fans would increasingly view it as akin to ancient Roman gladiatorial combat.

Others pushed back. Former NFL fullback Merrill Hoge — whose playing career was cut short by concussions — called Mr. Warner’s comments “uneducated” and “unacceptable,” arguing that football is relatively safe and that inactivity-related obesity is a greater threat to children than football-induced brain injuries. Mr. Limbaugh framed the debate as political, likening concern about the sport’s safety to “the Sierra Club calling to ban the SUV” and accusing “well-intentioned liberals” of attacking a sport they “think is too risky and dangerous.”

In an American Spectator article, conservative author Daniel J. Flynn echoed Mr. Hoge and Mr. Limbaugh. Noting that football causes fewer deaths per year than skiing and swimming and citing a study that football players live longer than their nonplaying male counterparts, he concluded that while “football is good for you,” “being a wuss” is not.

“There are people who don’t like football and are trying to use this to get rid of football,” said Mr. Flynn, author of “A Conservative History of the American Left” and a former high school football player. “They’re essentially killjoys. When the debate degenerates into banning the sport, it’s a cultural tic masquerading as a public health issue.”

Partisan football?

Similar sentiments surround first lady Michelle Obama’s healthy food advocacy and efforts to curb the use of trans fats in restaurant cooking, a pair of public health initiatives that have become culture war fodder — partisan footballs kicked around by liberals, conservatives and cable news bloviators alike.

Consider Montana, where last year state legislators were unable to pass a bill based on a national model that requires strict post-concussion return-to-play guidelines for young athletes, instead settling on a watered-down mandate requiring local officials to develop “risk-addressing protocols” that local school districts are under no obligation to adopt.

According to a FoxSports.com report, lawmakers balked at mandatory guidelines, citing concerns about civil liberty.

“We were told parents already know the risk their children are in when they play football,” state Sen. Bill Landen, a Republican, told FoxSports. “They didn’t want the state coming in and issuing mandates on this or that.”

The proper place of government regulation — and of risk in society — was at the heart of a recent public debate held at New York University on the future of college football. Describing the potential for brain damage, best-selling author Malcolm Gladwell argued that the sport should be banned, in part because schools have a paternalistic duty to protect their students; sportswriter and former college football player Jason Whitlock countered that America is a free country, and that citizens should have the freedom to enjoy things — such as alcohol, fast food and pornography — that aren’t necessarily good for them.

“We long ago decided as a nation that children will not have all adult freedoms until they reach a certain age,” said Michael Oriard, a former NFL player and retired professor of American literature and culture at Oregon State University. “Regarding pro football players knowing the risks and taking them freely, that’s a legitimate argument, even if it ignores the public costs if these players do become incapacitated later.”

Reminiscent of bickering over climate change, football reformers assert that current scientific evidence — such as a recent Virginia Tech study that found that 7- and 8-year-old football players can hit with as much force as college athletes — is strong enough to require major changes to the sport now; traditionalists, like retired NFL player Tim Green, want to see more proof. And much as contemporary conservatives decry a litigation explosion that erodes the personal responsibility ethic and enriches tort lawyers, online articles about more than 1,000 former players suing the NFL for failing to properly treat head trauma and disclose concussion risks are peppered with reader comments lambasting ex-athletes for trying to cash in.

“It’s not 100 percent of our readers, but it seems well over 50 percent who have the attitude of, ‘The players knew what they were getting into, I don’t want to hear any complaints that football is dangerous after you retire and run out of money,’ ” said Mike Florio, a former lawyer and owner of the popular NBC Sports website Profootballtalk.com. “These are the same people who would support tort reform. I don’t want to generalize, but I do get the impression that hard core football fans tend to be more conservative than liberal.”

Wrong lens?

Perhaps it’s inevitable in our binary political culture, but should football’s safety debate even be viewed through a left-right lens in the first place?

Mr. Oriard said politicizing the sport is “ridiculous, appalling and dangerous.” Mr. Flynn said it’s more accurate to see football’s current schism as a fight between those who played the game and those who did not.

Mr. Zirin said the best way to understand football is not as a sociocultural battlefield, but rather as a prosaic, potentially hazardous work environment.

“First, we need more information about head injuries and the science of this,” he said. “As with smoking, people need to be able to make an informed choice. Then, it’s like coal mining. We should make sure that the people who do these dangerous jobs work in as safe conditions as possible, and have all the benefits they can for the purposes of doing their jobs.”

That may prove easier said than done. At a 2009 House Judiciary Committee hearing, Rep. Linda Sanchez grilled NFL Commissioner Roger Goodell about the league’s handling of concussions and player safety, likening pro football to the tobacco industry. Meanwhile, Rep. Ted Poe questioned why Congress was getting involved, lamenting a potential future of two-hand touch and the “end of football as we know it.”

Predictably, Ms. Sanchez is a California Democrat. Mr. Poe is a Texas Republican. The battle lines, perhaps, already have been drawn.